Threads cutting machine



1941- X.IF. CAgTELLl 2,265,265

' THREADS CUTTING MACHINE.

File d June 2'7, 19:8 3 Sheets-Sheet 1 Mira/501512111,

Mfr QM flmxvfys X. F. CASTELLI THREADS CUTTING MACHINE Filed June 27,1939 3 Sheets-Sheet 2 JWVE/Y T xzwaw e 01672211,

. Hf/OFNEY Dec. 9, 1941.

X. F. CASTELLI THREADS CUTTING MACHINE Filed June 2'7, 1939 3Sheets-Sheet 3 VIE]? FFATMWSG'flHL/ awW B)" Patented Dec. 9, 1941 UNITEDSTATES PATENT OFFICE 2.265.265 'rn-anans cu'r'rmc MACHINE XavierFrancois Castelli, Paris, France Application June 27, 1939, Serial No.281,466

In France June 28, 1938 5 Claims.

My present invention has for its object 9. threads cutting or threadingmachine which operates as a horizontal lathe, but in which the piece tobe threaded is always revolving in the same direction.

Threading is performed in successive passes or courses the number ofwhich depends from the diameter and hardness of the piece to bethreaded.

The main features of the said machine consist in that the variations inthe pitch of the thread are obtained without the use of gears as inusual threading machines and that the relative depth of the successivepasses becomes automatically adjusted according to the overall depth ofthe thread.

According to my invention the cutting tool is carried by an ordinarylathe tool-holder, secured upon a longitudinally displaceable slide-bar;in order to adjust the pitch of the thread made by the machine, theratio between the number of revolutions of the machine main drivingshaft and the forward longitudinal travel of the toolholder is adjustedat will, by means of a removable plate provided with oblique sides,which is displaced at right angles to the travel of the tool-holderduring a given number of revolutions of the driving shaft (thus actingthrough one of its sides during such travel upon the tool holder),

and is subsequently rapidly carried back to its original position whilstthe driving shaft is further revolving.

The said plate may ular, trapesoidal, polygonal be of rectangular,triangor anyother form,

i. e. it may comprise any such desired number of oblique planes. Each ofsaid planes having a different obliquity may, owing to the positioningof the plate on its support, be caused at will to act upon thetool-holder, in order to move it longitudinally by means of anyconvenient gear.

According to the obliquity of the plane of the plate which will act uponthe tool-holder,-there will be obtained a thread of different pitch,since the tool-holder will be more or less displaced in the longitudinaldirection, depending from the value of said obliquity.

By securing the same plate in different positions on its support, itwill thus be possible to obtain as many thread pitches as saidplatecomprises oblique sides.

' Besides, it will be possible to obtain with the same plate so manyother series of thread pitches as the available ratios between thenumber of revolutions of the driving shaft and the shaft which causesthe displacement of the plate,

' turns to itsoriginal position,

To sum up, a single plate will provide so many thread pitches as suchplate comprises oblique sides and as many ratios are available betweenthe number of revolutionsof the main driving shaft and of the shaftcausing the displacement of said plate.

The displacement of the plate at right angles to the direction of travelof the tool-holder may be obtained by means of a cam carried by theabove mentioned shaft.

As stated passes and its successive travels-at right angles to the axisof revolution of the piece to be threaded (which must be each time moredeeply cut by the tool) but with a descending progressiori-may beobtained by means of a disc carrying on its periphery more or lessprojecting bosses acting upon the tool-holder through a two-armed linkedlever or any other convenient gear.

At the proper times, the said disc is itself successively rotated byfractions of revolutions for instance by means of a pawl and ratchetwheel drive (or otherwise) controlled by the revolution of the shaftwhich provides for the displacement of the oblique sided plate. Owing tothe said arrangement, when the plate having provided a longitudinaldisplacement of the tool-holder, rethe disc is automatically rotated bya fraction of revolution and a new more projecting boss becomes actingupon the tool for causing its deeper penetration during the subsequentpass, in the piece to be threaded.

My invention also comprises other features which will be describedbelow.

The accompanying drawings show by way of example an embodiment of theinvention.

In such drawings:

Fig. i is a plan view of the machine;

Fig. 2 is a front view;-

, Fig. 3 is a side view;

Fig. 4 is a detail view of the peripheral sideface cam.-

The machine comprises a frame I similar to a lathe with its head stockand its bed. A shaft 2 is rotatable at different speeds and carries aclutch gear comprising a fixed pulley 3 and a loose pulley 4; 5 is theclutch lever for trans: ferring the belt 6 from one pulley to the other.

The said lever is maintained in operation" by brake 9 which is appliedon the fixed pulley at the time of disengagement.

above, the tool acts by successive The main shaft 2 drives, by means ofa set of gears I0, I00, I01), I00, a shaft parallel to the shaft 2. Theshaft II is rotatable at a number of diiferentspeeds with respect to theshaft 2. Three speeds are here assumed, viz. 16, 32 and 64 revolutionsof the shaft 2 for one revolution of shaft Said shaft carries apcripheral side-face cam l2, shown Fig. 4, e. g. 270 in a regularlyascending slope, 15 without any slope, 60 indescending slope and 15without any slope.

The cam |2 operates a roller l3 secured on a part I 4 which slides atright angles to the shaft 2 betweentwo slide-bars I5 integral with theframe I. The part I4 is provided at its center witlia threaded rod l6(Figs. 1 and 2) and a vertical key l4 passing through the axis of therod "5. Said key is exactly parallel to the slide bars .|5. A spring |1maintains the roller l3 applied against the cam i9.

Plates of different shapes may be secured on the part or member l4, inexactly fixed positions with respect to the key M of the number l4, bythe threaded rod I6 through the handle l6.

- Said plates l8 (rectangles, triangles, trapezoids,

polygons) determine the pitch of the thread cut by the machine byvarying the ratio between the number of revolutions of the shaft 2 withrespect to the longitudinal forward travel of the cutting tool.

The plate l8 may for instance be provided with two grooves l8 incrossing arrangement, any of said grooves fitting on the key M accordingto the position given to the plate l8.

Their operation is as follows:

The threading tool I9 is secured in a support 20 sliding at right anglesto the axis of the shaft '2 between two guides 2| attached by means oftwo bolts 22 in a longitudinal slide bar 23 sliding in paralleldirection to the shaft 2 between the guides of the frame I. The support20 carries a slider 24 at right angles to the shaft 2 and maintainedbetween two micrometric screws 25 by means of a projecting square piece26 secured on the slider 24. Such micrometric screws adjust the forwardtravel of the tool against the piece to be threaded and consequently thediameter of the thread. They form a part of the support 20. I

The slider 24 is provided at its end with a roller 21 carried by aslider 28 which is adjustable vertically by means of a knob 29 acting ona micrometric screw 30. Under the action of a spring (not shown) theroller 21 tends to press strongly against a lever 3| pivoting around anaxis 32 and carrying a second arm 33 which is teeth, form different andprogressive projec-.

tions in order to act gradually through the action of rollers 34 and 21,upon the tool I9.

The combination of both lever arms 3| and 33 together with the action ofthe slider 23 upon the roller 21 enables, by removing the roller '21from the axis 32 or by drawing it nearer to said axis, to increase ordecrease at will the overall forwards travel caused by the action of theeight bosses of the disc 35 which are unvariable. In this way, by thesimple manipulation of roller 21, the eight passes may be performed on a0.20 or 0.24 inches), the forward travel of each pass being proportionalto the total depth of the thread and said combination forms acharacteristic feature of the machine. A complete The bosses 35' may bearranged as to their numbers and thicknesses for threading as follows:either in three passes (and in this case a revolution of the disccorresponds to three threads) or in four passes for two threads perrevolution,'or in five, six, eight, nine, ten, twelve or fifteen passes.The proportional amplifying or reducing action of the roller 21 isavailable whatever may be the number of bosses of the disc.

The rotation of the disc 35 is obtained by means of two sectors 36secured to one face of the cams l2 and acting upon a lever 31 integralwith a pawl 38 engaging a ratchet wheel 39 se-- cured to a shaft 40carrying the disc 35. The action of one of the sectors 36 disengages theroller 34 from one of the bosses of the disc 35 at the time when theroller l3 has completed its path along the 270 slope of the cam l2. The

roller 34 is thus between two bosses when' the roller l3 runs along the60 of descending slope of cam l2. At that time takes place the action ofthe second sector 36 which rotates the disc 35 in order to locate theroller 34 on the subsequent boss. The ratchet wheel 39 is providedlaterally with sectors 4| which act upon the pieces to be threaded areobtained by the action of disc 35; the action of plates l8 secured tothe sliding part |4 will now be precized. One of the sides of the plateI8 is in contact with a roller 42 attached on a vertical slider 43,which may be adjusted by a knob 44 between the guides of the frame 45attached to the longitudinal slider 23 carrying the tool-holder 20. Theside of plate I8 which is in contact with the roller 42 is not parallelto the sliders I5, it is arranged obliquely to the sliders and thedegree of obliquity is different for each of the four sides of plate l8(f. i. 6 mm., 12 mm., 18 mm., 24 mm.) (0.24, 0.48, 0.72, 0.96 in.) ofslope for 10 cm. (4 in.) in length.

When the machine is set in operation with the ratio of 16 to 1 betweenthe shafts 2 and H, the cam l2 will lift the plate '|8 after twelverevolutions of the shaft 2 (rotation of 270 over 360 of cam l2) and thetool will be displaced in the longitudinal direction of a distance equalto the obliquity of the oblique side or plane of the plate l8 actingupon the roller 42. When said obliquity is of 6 mm. (0.24 cm.)', thepitch will be 0.02 in.; if it is 12 mm. (0.48 in.) the pitch will be0.04 in.; said pitch will be 1.5 mm. (0.06 in.) for the slope of 18 mm.(0.72 in.) and of 2 mm. (0.08 in.) for a slope of 24 mm. (0.96 in.).

With the same plate l8 the obliquity of 6 mm.

(0.24 in.) will give'0.25 mm. (0.01 in.) pitches and 0.125 mm. (0.005)pitches if the ratios of 32 thread depth of 3, 4, 5 or 6 mm. (viz. 0.12,016,

and 64 are set between the shafts 2 and II by means of thegear l0b.

to its starting position. A further action of the second sector 36places the roller 34 on the subsequent boss, more projecting than" thepreceding one and the tool penetrates more deeply;

the thread, the sector ll is acting on the pawl I to stop the machine. V

In order to adjust the longitudinal travel of strongly descending slopeof cam ii, the plate 18 is lowered and the tool is brought back r sibleto cut at the same time two threads of same pitches of differentdiameters.

By the use of curved friction planes instead of straight plane threadswith ascending or descending spaces will be obtained.

With broken planes it is possible to obtain, in a same proceeding,different pitches succeeding to one anotheri .For obtaining leftpitches, there shall-merely have the main shaft rotated inthe oppositedirection, the face of the cam and that of the disc turned back, and thecutting tool reversed.

' the cycle is renewed until after completion of a the tool, the rolleri3 is placed at the higher part of the cam -l2, and the knob 44 isoperated which by causin' the roller 42 to run up along the oblique sideof plate l8 moves the slider 23 towards the left side of Fig. 2 and thusdetermines the threading plane located farther at right with. respect tothe shaft 2. In order to adjust the opposite plane, located farther atleft with respect to the shaft 2, which plane constitutes the originalplane of the thread the knob 46 is operated, said knob acting on themicrometric screw 41 integral with the longitudinal slider 23 by meansof support 48 and acting as a stop on the frame I. A washer 49 enablesto lock the screw 41 when the adjusting operation is completed.

The speed of revolution is the speed admitted as circumferential speedof'the cutting tool for the metal being threaded. The speed is constantand the time needed by the tool for returning to its engaging positionis only the third of the time taken by threading. The accuracy in' thelongitudinal range of travel of the tool enables to obtain in massproduction very diiilcult and precise threads.

. The use of the oblique planes of the plate l8 for the determination ofpitches enables to obtain any kind of pitches. When for instance theoblique plane exerts its action in twelve revolutions of the main shaft,for obtaining a given pitch it is only necessary to take the linearlength.

of twelve threads and to give to the oblique plane, over 10 cm. (4 in.)length. an obliquity equal to such linear length. Thus-with a slope of 2in. per 4 in. and by employing the suitable of the three ratios 16, 32,64 between the shafts 2 and H, the pitches of 6, 12 and 24 threads perinch,

will be obtained. With a slope ofl.5 in. the

. pitches of 8 and 16 threads per inch will. be

obtained. By means of two trapezoidal plates Hi all Whitworth pitchescomprised between 4 and 24 threads per inch will be obtained.

For special pitches, the plate 18 may be replaced by an alhidade withcircular sector provided with a scale and nonius, pivoted about an axisand adjustable by means of a micrometric screw; in this way all anglesmay be determined and consequently all pitches.

It is understood that the above figures of speed, obliquity of likeratios are only given by way of example.

The machine can operate as separat unit or in combination withanother=machine. Since threading is performed at the cutting velocity of a toolthe threads can be cut in pieces which are revolving on machines forother works, since there is no reversing in the direction of rotation.The time of threading enables indeed to spare labour. With a convenienttool, it is also pos- The machine may be realized with hollow shaft forthreading tubes, cylinders When the pieces to be threaded shall besupported by their both ends, a sliding movable head stock or any othermember for supporting these and rotating a work piece, an obliquesliding plate for the adjustment of the pitch of the thread to be out,said plate comprising at least one oblique side and acting on saidtool-holder, a

disc, means for intermittently rotating said disc for successivefractions of a total revolution, bosses on the periphery of said discputting the tool more deeply into the work pieces after each workingpass, means for automatically stopping the machine when all bosses haveworked on the tool and the threading is ended.

2. Threading machine comprising a longitudinally movable tool holder,means for supporting and rotating a work piece, an oblique sliding platefor the adjustment of the pitch of the thread to be out, said platecomprising at least one oblique side and acting on'said tool holder, anoscillating lever pushing said tool holder towards the object to bethreaded, a disc, means for intermittently rotating said disc for successive fractions of a total revolution, bosses on the peripheryof saiddisc, said bosses acting on the oscillating lever for putting the toolmore deeply into the work piece after.each working pass.

Threading machine comprising a longitudinally movable tool holder, meansfor supporting and rotating a work piece, an oblique sliding plate forthe adjustment of the pitch of the thread to be cut, said platecomprising at least one obliqueside and acting on said tool holder, anoscillating lever pushing said tool holder towards the object to bethreaded, a disc, means for intermittently rotating said disc forsuccessive fractions of a total revolution, bosses on the periphery ofsaid disc, said bosses acting on the oscillating lever for putting thetool more deeply nally movable tool holder, mean for supporting androtating a work piece, an oblique sliding plate for the adjustment ofthe pitch of the thread to be out, said plate comprising at least oneoblique side and acting on said tool holder, a part mounted slidably onthe tool holder, an oscillating lever bearing on said part to push thetool holder towards the work piece, a disc,

means forintermittently rotating said disc for successive fractions of atotal revolution, bosses on the periphery of said disc, said bossesacting on the oscillating lever for putting the tool more deeply intothe work piece after each working pass, and a setting device fordisplacing the slidable part on the tool holder to vary the actual 7length of the corresponding'arm of the oscillating lever.

5. Threading machine comprising a. longitudinally movable tool holder,means for supporting 5 and rotating a work piece, an oblique slidingplate for the adjustment of the pitch of the thread to be cut, saidplate comprising at least,

one oblique side and acting on said tool holder, an oscillatingleverpushing said tool holder to- .wards the work piece, a disc, means forinterafter each working pass, means for varying the actual length of onearm of said oscillating lever, and means for automatically stopping themachine when all bosses have worked on the tool 10 and the threading isended.

XAVIER moors CASTELIJ.

